1. Field of the Invention
The subject invention relates to a heat exchanger assembly including a first heat exchanger and a second heat exchanger disposed in parallel relationship to one another for greater heat transfer capacity.
2. Description of the Prior Art
The heat exchanger assemblies to which the subject invention pertains are systems which include overlapping or double flows of working fluid to improve performance while minimizing space requirements. The design and manufacture of such a heat exchanger normally includes parallel communication manifolds which are of a round cross sectional shape to optimally contain the pressures normally occurring in such systems. Such cylindrical manifolds require a means of fluid communication between the side by side and parallel communication manifolds to attain the overlapping or double flow of working fluid in the heat exchanger assembly.
One such heat exchanger assembly is disclosed in U.S. Patent Application 2007/0193731 to Lamich, et al, wherein the heat exchanger assembly includes a first heat exchanger assembly and a second heat exchanger assembly disposed in parallel and sandwiched relationship. The first heat exchanger assembly includes a cylindrical communication manifold disposed parallel and adjacent to a cylindrical communication manifold of the second heat exchanger assembly. A flow connection is disposed between the two manifolds at adjacent the bottom ends of the communication manifolds and defines one fluid passage to establish fluid communication from the first heat exchanger assembly to the second heat exchanger assembly. However, the flow connection only at one end of the communication manifolds does not provide the distribution of coolant along and between the entire length of the communication manifolds.
Another heat exchanger assembly is disclosed in U.S. Patent Application 2002/0066553 to Fischer, et al, wherein the communication manifolds of the first and second heat exchanger assemblies define a plurality of communication orifices disposed linearly along the manifolds and wherein the communication orifices of the communication manifold of the first heat exchanger assembly are coaxial with the communication orifices of the communication manifold of the second heat exchanger assembly. This heat exchanger assembly establishes the communication manifolds disposed flush to one another. As a result, the communication manifolds are planar at the point of fluid communication which requires tight manufacturing tolerances to establish fluid communication between the first and second heat exchanger assemblies.
Additionally, it is common in a double flow heat exchanger, with cylindrical manifolds, to utilize a series of U-shaped return tubes disposed along the bottoms of the two parallel communication manifolds to establish fluid communication between the two heat exchanger assemblies. However, this arrangement requires the utilization of numerous individual return tubes which increases the manufacturing time, labor and costs. Each of the U-shaped return tubes must be handled individually and each return tube requires two braze joints to fixture the return tube to the communication manifolds. Additionally, since the return tubes are disposed along the bottom of the communication manifolds, the use of such return tubes increases the overall height of the heat exchanger assembly.
Alternatively, in place of a series of tubes, it is common to utilize a single U-shaped return tube which extends from and is brazed to the ends of the communication manifolds to establish fluid communication between the two heat exchanger assemblies. However, like the previously disclosed heat exchanger assembly, the disposition of the return tube only at one end of the communication manifolds does not provide the distribution of coolant along and between the entire length of the communication manifolds.
Although the prior art heat exchangers are able to communicate a working fluid from a first heat exchanger assembly to a second heat exchanger assembly, there remains a need for a communication design for optimizing fluid communication between a first and second heat exchanger assembly while reducing time, labor and cost during the manufacturing process.